Encapsulated-metal vertical-interdigitated capacitor and damascene method of manufacturing same

• US 6,441,419 B1
• Filed: 03/15/2000
• Issued: 08/27/2002
• Est. Priority Date: 03/31/1998
• Status: Expired due to Term

• Current Assignee: Bell Semiconductor, LLC (Hilco Inc. (d/b/a Hilco Global))
• Original Assignee: LSI Logic Corporation (Broadcom, Inc.)
• Inventors: Johnson, Gregory A., Miller, Gayle, Taravade, Kunal
• Primary Examiner(s): Thomas, Tom
• Assistant Examiner(s): Nguyen, Cuong Quang
• Application Number:
  US09/525,489
• Time in Patent Office: 895 Days
• Field of Search: 257/295-310, 257/530-535, 438/253-254, 438/391-399
• US Class Current: 257/296
• CPC Class Codes: H01L 21/76838 characterised by the formation and the after-treatment of the conductors etching for patterning the conductors H01L21/3213
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/7687 Thin films associated with contacts of capacitors
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 21/76895 Local interconnects; Local pads, as exemplified by patent document EP0896365
• CPC Class Codes: H01L 23/5223 Capacitor integral with wiring layers
• CPC Class Codes: H01L 27/0805 Capacitors only
• CPC Class Codes: H01L 28/40 Capacitors
• CPC Class Codes: H01L 28/60 Electrodes
• CPC Class Codes: H01L 28/90 having vertical extensions
• CPC Class Codes: H01L 28/91 made by depositing layers, e.g. by depositing alternating conductive and insulating layers
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

An integrated circuit includes a vertical-interdigitated capacitor located between an upper interconnect layer and a lower interconnect layer. Both interconnect layers include conductors formed of a metal capable of atom diffusion or ion migration, such as copper. The capacitor plates contact an interconnect layer conductor to create barrier layers to prevent atom diffusion or ion migration from the conductors at the contact locations. Additional barrier layers contact the conductors at locations other than where the capacitor plate portions contact the conductors, and the additional barrier layers are preferably formed of the same material and at the same time that one of the plates is formed. The integrated circuit may include a via plug interconnect extending between conductors of upper and lower interconnect layers, with a plug barrier layer surrounding the plug material to prevent atom diffusion or ion migration from the plug material.

Claims

1. In an integrated circuit (IC) having upper interconnect layer and a lower interconnect layer in which each interconnect layer comprises a conductor formed of a metal capable of atom diffusion or ion migration, an improved capacitor located between the upper and lower interconnect layers comprising:

upper and lower capacitor plates;

capacitor dielectric material separating the plates;

the upper plate includes a plurality of U-shaped portions;

the lower plate includes a plurality of U-shaped portions which extend generally parallel to the U-shaped portions of the upper plate;

each U-shaped portion includes a pair of leg portions connected at a base portion;

the lower plate having a portion directly contacting a conductor positioned within the lower interconnect layer;

the upper plate having a portion directly contacting a conductor positioned within the upper interconnect layer;

the portions of the upper and lower plates which directly contact the conductors forming plate barrier layers to prevent atom diffusion or ion migration from the conductors at those direct contact locations; and

the conductor of the upper interconnect layer includes a plurality of finger portions which project into a plurality of the U-shaped portions of the upper plate.

2. An IC as defined in claim 1 wherein the conductors are substantially copper.

3. An IC as defined in claim 1 further comprising:

additional barrier layers contacting the conductors at locations other than at the contact locations of the upper and lower plates to prevent atom diffusion or ion migration from the conductors at the other locations; and

the plate barrier layers and the additional barrier layers encapsulate the conductors to prevent atom diffusion or ion migration.

4. An IC as defined in claim 3 wherein the additional barrier layers contacting the conductors are formed of the same material as the material from which at least one of the plates is formed.

5. An IC as defined in claim 3 further comprising:

a via plug interconnection extending between conductors of the upper and lower interconnect layers, the via plug interconnection including plug material formed of a metal capable of atom diffusion or ion migration; and

a plug barrier layer surrounding the plug material.

6. An IC as defined in claim 1 wherein the U-shaped portions of the upper plate surround the finger portions to form a barrier to prevent atom diffusion or ion migration from the finger portions.

7. An IC as defined in claim 1 further comprising:

a via plug interconnection extending between conductors of the upper and lower interconnect layer, the via plug interconnection including plug material formed of a metal capable of atom diffusion or ion migration; and

a plug barrier layer surrounding the plug material.

8. In an integrated circuit (IC) having upper interconnect layer and a lower interconnect layer in which each interconnect layer comprises a conductor formed of a metal capable of atom diffusion or ion migration, an improved capacitor located between the upper and lower interconnect layers comprising:

upper and lower capacitor plates;

capacitor dielectric material separating the plates;

the upper plate includes a plurality of U-shaped portions;

the lower plate includes a plurality of U-shaped portions which extend generally parallel to the U-shaped portions of the upper plate;

each U-shaped portion includes a pair of leg portions connected at a base portion;

the base portion of the lower plate directly contacting a conductor positioned within the lower interconnect layer;

the upper plate having a portion directly contacting a conductor positioned within the upper interconnect layer;

the portions of the upper and lower plates which directly contact the conductors forming plate barrier layers to prevent atom diffusion or ion migration the conductors at those direct contact locations;

a via plug interconnection extending between conductors of the upper and lower interconnect layers, the via plug interconnection including plug material formed of a metal capable of atom diffusion or ion migration;

a plug barrier layer surrounding the plug material; and

the plug material and the conductors are of substantially the same metal.

9. An IC as defined in claim 8 wherein the plug barrier layer and one of the plates of the capacitor are of substantially the same material.

10. An IC as defined in claim 9 wherein the plug barrier layer and one of the plates of the capacitor are integrally, connected.

11. An IC as defined in claim 10 wherein:

the metal of the conductors and the plug material is substantially copper; and

the material of the plug barrier layers and material of the capacitor plates include a metal selected from the group consisting of tantalum, tantalum nitride, titanium nitride, and molybdenum.

12. An IC as defined in claim 8 wherein:

the conductor of the upper interconnect layer includes at least one finger portion which projects into one of the U-shaped portions of the upper plate.

13. In an integrated circuit (IC) having upper interconnect layer and a lower interconnect layer in which each interconnect layer comprises a conductor formed of a metal capable of atom diffusion or ion migration, an improved capacitor located between the upper and lower interconnect layers comprising:

upper and lower capacitor plates;

capacitor dielectric material separating the plates;

the upper plate includes a plurality of U-shaped portions;

the lower plate includes a plurality of U-shaped portions which extend generally parallel to the U-shaped portions of the upper plate;

each U-shaped portion includes a pair of leg portions connected at a base portion;

the conductor of the upper interconnect layer includes at least one finger portion which projects into one of the U-shaped portions of the upper plate;

the base portion of the lower plate contacting a conductor positioned within the lower interconnect layer;

the upper plate having a portion contacting a conductor positioned within the upper interconnect layer; and

the portions of the upper and lower plates which contact the conductors forming plate barrier layers to prevent atom diffusion or ion migration from the conductors at the contact locations.

14. An IC as defined in claim 13 wherein one of the U-shaped portions of the upper plate surrounds the finger portion of the conductor and forms the barrier layer to prevent atom diffusion or ion migration from the finger portion.

15. An IC as defined in claim 13 wherein:

the interconnect layers extend substantially horizontally and are vertically spaced with respect to one another; and

the leg portions of the U-shaped portions extend substantially vertically between the interconnect layers.

16. An IC as defined in claim 15 further comprising:

interlayer dielectric material separating the vertically spaced interconnect layers; and

wherein;

the capacitor is located substantially in the interlayer dielectric material.

17. In an integrated circuit (IC) having upper interconnect layer and a lower interconnect layer in which each interconnect layer comprises a conductor formed of a metal capable of atom diffusion or ion migration, an improved capacitor located between the upper and lower interconnect layers comprising:

upper and lower capacitor plates;

capacitor dielectric material separating the plates;

the upper plate includes a plurality of U-shaped portions;

the lower plate includes a plurality of U-shaped portions which extend generally parallel to the U-shaped portions of the upper plate;

each U-shaped portion includes a pair of leg portions connected at a base portion;

the U-shaped portions are horizontally separated in the upper and lower plates by spaces;

the conductor of the upper interconnect layer includes a finger portion which projects into the U-shaped portion of the upper plate

the conductor of the upper interconnect layer includes at least one additional finger portion which projects into the space between the U-shaped portions of the lower plate;

the base portion of the lower plate having a portion contacting a conductor positioned within the lower interconnect layer to form a plate barrier layer to prevent atom diffusion or ion migration from the conductor at that contact location;

the upper plate having a portion contacting a conductor positioned within the upper interconnect layer to form a plate barrier layer to prevent atom diffusion or ion migration from the conductor at that contact location;

additional barrier layers contacting each finger portion to prevent atom diffusion or ion migration from the conductors at the locations of each finger portion; and

the plate barrier layers and the additional barrier layers encapsulate the conductors to prevent atom diffusion or ion migration.

18. An IC as defined in claim 17 wherein:

the additional barrier layers which contact the finger portions constitute an extension of the plate barrier layer of at least one of the upper or lower plates.

19. An IC as defined in claim 18 wherein:

all of the U-shaped portions of the lower plate are commonly connected to a single segment of the conductor of the lower interconnect layer.

20. An IC as defined in claim 17 further comprising:

a via plug interconnection extending between conductors of the upper and relatively lower interconnect layers, the via plug interconnection including plug material formed of a metal capable of atom diffusion or ion migration;

a plug barrier layer surrounding the plug material; and

wherein;

the plug material and the conductors are of substantially the same metal; and

the plug barrier layer and one of the plates of the capacitor are of substantially the same material.